The development of high-capacity networks has been driven by the need to establish high-bandwidth data connections among remote sites, for instance, between clients and servers. Most often, the communications infrastructure for such a network is provided by one or more long-distance carriers serving the geographic region that encompasses the various remote sites. A carrier may lease fiber optic lines to customers wishing to establish high-capacity connections. Within the carrier's network, optical switching nodes are then configured to support the desired connections.
Usually, a carrier leases its fiber optic lines with a view to long-term usage thereof. Thus, switch configurations established at the time of provisioning the high-capacity connections are expected to remain in place for a period of months or years. Therefore, the switches in the network can be configured manually with virtually no impact on cost or quality of service provided.
However, it is not feasible to manually configure a large number of switches when dealing with a network whose size and/or topology are in constant evolution. Furthermore, the manual configuration of switches cannot accommodate situations in which the bandwidth or quality of service requirements of the traffic to be transported through the network is time-varying or if there is urgency in establishing new high-capacity connections through the network. Although it is desirable to provide switches which are automatically reconfigurable as a function of changes to the topology and traffic load of the network, such a capability is currently not available.
Moreover, the most common approach to establishing end-to-end data connections in current optical networks relies on the utilization of the same wavelength, say λX, along a manually configured path throughout the network. This prevents the establishment of other data connections using λX as an end-to-end wavelength if part of the path corresponding to the new connection intersects part of the path corresponding to the original connection. This places a severe constraint on wavelength usage in a current optical network, with the effect of drastically reducing the overall bandwidth efficiency in the network.
Thus, it is apparent that there is a need in the industry to provide an optical switching node which overcomes the above stated disadvantages.